With rapid development of Internet, to achieve high-speed forward processing of messages, a specialized traffic management chip is generally adopted in a router to complete caching and scheduling output of high-speed data streams. Moreover, scheduling shall be conducted as required by Quality of Service (QoS) in accordance with an issued authorization.
A specific processing procedure generally includes: first receiving messages to complete caching of message queueing, i.e., message enqueuing is completed so as to update queue information, and an authorization would be issued by an authorization system so that message dequeuing would further update queue information and consume authorizations. A scheduling module judges whether a queue is required to be scheduled according to real-time queue information and a queue authorized value. If the queue has a message and an authorization, one message of the queue is to be scheduled for dequeuing processing as well as updates of authorization deduction and queue depth.
Meanwhile, a queue management must be able to process all IP packets of 64-16384 bytes at wire speed. At an Ethernet environment of 200 Gbps, a typical relationship between an IP packet length and an IP packet forward rate is shown in Table 1, where the unit of the IP packet forward rate is Million Packet Per Second (MPPS).
TABLE 1IP Packet LengthIP Packet Forward Rate(Byte)(MPPS)64297.6190476128168.918918925690.5797101451246.9924812102423.94636015150016.44736842163841.524018532
It is known from Table 1 that a chip needs to provide a packet processing capability of 300 MPPS to meet requirements. At a system clock of 600 MHz, enqueuing and dequeuing operations are processed once every two cycles correspondingly, and a bandwidth authorized is up to 50 MPPS; and for scheduling, enqueuing, dequeuing and authorization trigger shall be processed simultaneously and a bandwidth is required to reach 650 MPPS. However, such bandwidth requirements cannot be achieved through division of time slots. If a method of crowding enqueuing through an authorization is adopted, an enqueuing bandwidth will not be ensured and messages of some bytes will not reach wire speed. These problems are required to be solved.